function buildQueueFingerprint(url: string, streamer: string, date: string, customClip?: CustomClip): string {
    const clipFingerprint = customClip
        ? [
            'clip',
            customClip.startSec,
            customClip.durationSec,
            customClip.startPart,
            customClip.filenameFormat,
            (customClip.filenameTemplate || '').trim().toLowerCase()
        ].join(':')
        : 'vod';

    return [
        (url || '').trim().toLowerCase().replace(/^https?:\/\/(www\.)?/, ''),
        (streamer || '').trim().toLowerCase(),
        (date || '').trim(),
        clipFingerprint
    ].join('|');
}

let lastQueueRenderFingerprint = '';

function getQueueRenderFingerprint(items: QueueItem[]): string {
    const lang = typeof currentLanguage === 'string' ? currentLanguage : 'en';
    const pieces = items.map((item) => [
        item.id,
        item.status,
        Math.round((Number(item.progress) || 0) * 10),
        item.currentPart || 0,
        item.totalParts || 0,
        item.speed || '',
        item.eta || '',
        item.progressStatus || '',
        item.last_error || '',
        item.mergeGroup?.mergePhase || ''
    ].join(':'));

    return `${lang}|${pieces.join('|')}`;
}

function hasActiveQueueDuplicate(url: string, streamer: string, date: string, customClip?: CustomClip): boolean {
    const target = buildQueueFingerprint(url, streamer, date, customClip);
    return queue.some((item) => {
        if (item.status !== 'pending' && item.status !== 'downloading' && item.status !== 'paused') {
            return false;
        }

        return buildQueueFingerprint(item.url, item.streamer, item.date, item.customClip) === target;
    });
}

async function addToQueue(url: string, title: string, date: string, streamer: string, duration: string): Promise<void> {
    if ((config.prevent_duplicate_downloads as boolean) !== false && hasActiveQueueDuplicate(url, streamer, date)) {
        alert(UI_TEXT.queue.duplicateSkipped);
        return;
    }

    queue = await window.api.addToQueue({
        url,
        title,
        date,
        streamer,
        duration_str: duration
    });
    renderQueue();
}

async function removeFromQueue(id: string): Promise<void> {
    queue = await window.api.removeFromQueue(id);
    renderQueue();
}

async function clearCompleted(): Promise<void> {
    queue = await window.api.clearCompleted();
    renderQueue();
}

async function retryFailedDownloads(): Promise<void> {
    queue = await window.api.retryFailedDownloads();
    renderQueue();
}

function getQueueStatusLabel(item: QueueItem): string {
    if (item.status === 'completed') return UI_TEXT.queue.statusDone;
    if (item.status === 'error') return UI_TEXT.queue.statusFailed;
    if (item.status === 'paused') return UI_TEXT.queue.statusPaused;
    if (item.status === 'downloading') return UI_TEXT.queue.statusRunning;
    return UI_TEXT.queue.statusWaiting;
}

function getQueueProgressText(item: QueueItem): string {
    if (item.status === 'completed') return '100%';
    if (item.status === 'error') return UI_TEXT.queue.progressError;
    if (item.status === 'paused') return UI_TEXT.queue.progressReady;
    if (item.status === 'pending') return UI_TEXT.queue.progressReady;
    if (item.progress > 0) return `${Math.max(0, Math.min(100, item.progress)).toFixed(1)}%`;
    return item.progressStatus || UI_TEXT.queue.progressLoading;
}

function getQueueMetaText(item: QueueItem): string {
    if (item.status === 'error' && item.last_error) {
        return item.last_error;
    }

    const parts: string[] = [];

    if (item.currentPart && item.totalParts) {
        parts.push(`${UI_TEXT.queue.part} ${item.currentPart}/${item.totalParts}`);
    }

    if (item.speed) {
        parts.push(`${UI_TEXT.queue.speed}: ${item.speed}`);
    }

    if (item.eta) {
        parts.push(`${UI_TEXT.queue.eta}: ${item.eta}`);
    }

    if (!parts.length && item.status === 'pending') {
        parts.push(UI_TEXT.queue.readyToDownload);
    }

    if (!parts.length && item.status === 'paused') {
        parts.push(UI_TEXT.queue.statusPaused);
    }

    if (!parts.length && item.status === 'downloading') {
        parts.push(item.progressStatus || UI_TEXT.queue.started);
    }

    if (!parts.length && item.status === 'completed') {
        parts.push(UI_TEXT.queue.done);
    }

    if (!parts.length && item.status === 'error') {
        parts.push(UI_TEXT.queue.failed);
    }

    return parts.join(' | ');
}

function toggleQueueSelection(id: string): void {
    const index = selectedQueueIds.indexOf(id);
    if (index >= 0) {
        selectedQueueIds.splice(index, 1);
    } else {
        selectedQueueIds.push(id);
    }
    renderQueue();
    updateMergeGroupButton();
}

function updateMergeGroupButton(): void {
    const btn = byId<HTMLButtonElement>('btnMergeGroup');
    if (!btn) return;

    // Clean up selections: only keep IDs that are still pending in queue
    const validIds = new Set(
        queue.filter(item => item.status === 'pending' && !item.mergeGroup).map(item => item.id)
    );
    selectedQueueIds = selectedQueueIds.filter(id => validIds.has(id));

    if (selectedQueueIds.length >= 2) {
        btn.style.display = '';
        btn.textContent = `${UI_TEXT.mergeGroup.btn} (${selectedQueueIds.length})`;
        btn.disabled = false;
    } else {
        btn.style.display = 'none';
    }
}

async function createMergeGroupFromSelection(): Promise<void> {
    if (selectedQueueIds.length < 2) return;

    const ids = [...selectedQueueIds];
    selectedQueueIds = [];
    queue = await window.api.createMergeGroup(ids);
    renderQueue();
    updateMergeGroupButton();
}

function updateQueueItemProgress(progress: DownloadProgress): void {
    const items = byId('queueList').children;
    const idx = queue.findIndex(i => i.id === progress.id);
    if (idx < 0 || idx >= items.length) return;

    const el = items[idx];
    const bar = el.querySelector('.queue-progress-bar') as HTMLElement;
    const text = el.querySelector('.queue-progress-text') as HTMLElement;
    const meta = el.querySelector('.queue-meta') as HTMLElement;

    if (bar) {
        const pct = progress.progress > 0 ? Math.min(100, progress.progress) : 0;
        bar.style.width = `${pct}%`;
        bar.className = `queue-progress-bar${progress.progress <= 0 ? ' indeterminate' : ''}`;
    }
    if (text) text.textContent = getQueueProgressText(queue[idx]);
    if (meta) meta.textContent = getQueueMetaText(queue[idx]);
}

function toggleQueueDetails(id: string): void {
    const el = document.getElementById(`details-${id}`);
    if (el) el.style.display = el.style.display === 'none' ? 'block' : 'none';
}

function initQueueDragDrop(): void {
    const list = byId('queueList');

    list.addEventListener('dragstart', (e: DragEvent) => {
        const el = (e.target as HTMLElement).closest('.queue-item') as HTMLElement;
        if (!el) return;
        draggedQueueItemId = el.dataset.id || null;
        el.classList.add('dragging');
        if (e.dataTransfer) e.dataTransfer.effectAllowed = 'move';
    });

    list.addEventListener('dragover', (e: DragEvent) => {
        e.preventDefault();
        if (e.dataTransfer) e.dataTransfer.dropEffect = 'move';
    });

    list.addEventListener('drop', (e: DragEvent) => {
        e.preventDefault();
        const target = (e.target as HTMLElement).closest('.queue-item') as HTMLElement;
        if (!target || !draggedQueueItemId) return;
        const targetId = target.dataset.id;
        if (!targetId || targetId === draggedQueueItemId) return;

        const fromIdx = queue.findIndex(i => i.id === draggedQueueItemId);
        const toIdx = queue.findIndex(i => i.id === targetId);
        if (fromIdx < 0 || toIdx < 0) return;
        const [moved] = queue.splice(fromIdx, 1);
        queue.splice(toIdx, 0, moved);
        window.api.reorderQueue(queue.map(i => i.id));
        renderQueue();
    });

    list.addEventListener('dragend', () => {
        draggedQueueItemId = null;
        document.querySelectorAll('.queue-item.dragging').forEach(el => el.classList.remove('dragging'));
    });
}

function renderQueue(): void {
    if (!Array.isArray(queue)) {
        queue = [];
    }

    const list = byId('queueList');
    byId('queueCount').textContent = String(queue.length);
    const retryBtn = byId<HTMLButtonElement>('btnRetryFailed');
    const hasFailed = queue.some((item) => item.status === 'error');
    retryBtn.disabled = !hasFailed;

    const renderFingerprint = getQueueRenderFingerprint(queue);
    if (renderFingerprint === lastQueueRenderFingerprint) {
        return;
    }

    if (queue.length === 0) {
        lastQueueRenderFingerprint = renderFingerprint;
        list.innerHTML = `<div style="color: var(--text-secondary); font-size: 12px; text-align: center; padding: 15px;">${UI_TEXT.queue.empty}</div>`;
        return;
    }

    list.innerHTML = queue.map((item: QueueItem) => {
        const safeTitle = escapeHtml(item.title || UI_TEXT.vods.untitled);
        const safeStatusLabel = escapeHtml(getQueueStatusLabel(item));
        const safeProgressText = escapeHtml(getQueueProgressText(item));
        const safeMeta = escapeHtml(getQueueMetaText(item));
        const isClip = item.customClip ? '* ' : '';
        const hasDeterminateProgress = item.progress > 0 && item.progress <= 100;
        const progressValue = item.status === 'completed'
            ? 100
            : (hasDeterminateProgress ? Math.max(0, Math.min(100, item.progress)) : 0);
        const progressClass = item.status === 'downloading' && !hasDeterminateProgress ? ' indeterminate' : '';

        const isMergeGroup = !!item.mergeGroup;
        const showSelector = item.status === 'pending' && !isMergeGroup;
        const selectionIndex = selectedQueueIds.indexOf(item.id);
        const isSelected = selectionIndex >= 0;
        const mergeIcon = isMergeGroup
            ? '<svg class="merge-group-icon" viewBox="0 0 24 24" fill="currentColor" width="14" height="14"><path d="M17 20.41L18.41 19 15 15.59 13.59 17 17 20.41zM7.5 8H11v5.59L5.59 19 7 20.41l6-6V8h3.5L12 3.5 7.5 8z"/></svg> '
            : '';
        const mergeMetaExtra = isMergeGroup
            ? ` (${UI_TEXT.mergeGroup.metaLabel.replace('{count}', String(item.mergeGroup!.items.length))})`
            : '';

        return `
            <div class="queue-item${isMergeGroup ? ' merge-group' : ''}" draggable="${item.status === 'pending' ? 'true' : 'false'}" data-id="${item.id}">
                ${showSelector
                    ? `<div class="queue-selector${isSelected ? ' selected' : ''}" onclick="toggleQueueSelection('${item.id}')">${isSelected ? selectionIndex + 1 : ''}</div>`
                    : ''
                }
                <div class="status ${item.status}"></div>
                <div class="queue-main">
                    <div class="queue-title-row">
                        <div class="title" title="${safeTitle}" onclick="toggleQueueDetails('${item.id}')" style="cursor:pointer">${mergeIcon}${isClip}${safeTitle}</div>
                        <div class="queue-status-label">${safeStatusLabel}</div>
                    </div>
                    <div class="queue-meta">${safeMeta}${mergeMetaExtra}</div>
                    <div class="queue-progress-wrap">
                        <div class="queue-progress-bar${progressClass}" style="width: ${progressValue}%;"></div>
                    </div>
                    <div class="queue-progress-text">${safeProgressText}</div>
                    <div class="queue-details" id="details-${item.id}" style="display:none">
                        <div>URL: ${escapeHtml(item.url)}</div>
                        <div>Streamer: ${escapeHtml(item.streamer)}</div>
                        <div>Dauer: ${escapeHtml(item.duration_str)}</div>
                        <div>Datum: ${escapeHtml(new Date(item.date).toLocaleString())}</div>
                    </div>
                </div>
                <span class="remove" onclick="removeFromQueue('${item.id}')">x</span>
            </div>
        `;
    }).join('');

    updateMergeGroupButton();
    lastQueueRenderFingerprint = renderFingerprint;
}

async function toggleDownload(): Promise<void> {
    if (downloading) {
        await window.api.pauseDownload();
        return;
    }

    const started = await window.api.startDownload();
    if (!started) {
        renderQueue();
        alert(UI_TEXT.queue.emptyAlert);
    }
}